246 THE COMMON SENSES 



What is the visual purple? 



How may an optogram be obtained? 



What supplies the normal stimulus to the retina? 



Give the course of the optic fibers. 



What constitutes the primary vision centre? 



Upon what physical conditions does the sensation of light depend? 



How can it be shown that luminosity is recognized more easily by the 

 eye than color? 



How do different portions of the retina vary in their power to distinguish 

 color? 



Give the various phases of the activity of the retina when stimulated. 



Distinguish between positive and negative after-images. 



What is irradiation? 



What is the relation of color to white light? 



Discuss the color theories. 



How is color blindness explained? 



What is the proportion of color blind in men and women? What reason 

 can be given for this? 



Discuss the perception of distance. 



Discuss binocular vision. 



Discuss the correction for the inversion of the retinal image. 



Upon what does clearness of vision depend? 



Where are the physical vibrations of sound transformed, into nervous 

 impulses? 



How do the sound waves of the air reach the organ of Corti? 



Are the organs of Corti absolutely essential to the appreciation of musical 

 tones? 



How are the impulses conveyed from the ear to the brain? 



What is subjective hearing and its causes? 



Upon what factors do musical sounds depend? 



How do noises differ from musical sounds? 



What is the musical range of the ear? 



What is the range of audibility of the ear? 



How is the distance of sounds estimated? 



Discuss the power of the ear to appreciate small intervals of time. 



What is meant by equilibrium of the body? 



How is the sense of equilibrium brought about? 



What is the effect of injury to the semicircular canals of an animal? 



What proof is there that the semicircular canals aid in preserving equi- 

 librium? 



What is the situation of the olfactory mucous membrane? 



What is the condition of substances that excite smell? 



What is the importance of smell in the lower animals? 



Give instances of the delicacy of the power of smell. 



Give the course of the olfactory fibers. 



Discuss the relation of common sensibility and smell. 



What is the location of the sense organs of taste? 



What are the nerves of taste? 



What is the relation of smell to taste? 



Does taste depend upon concentration or on the quantity of the stimu- 

 lating substance? 



How is taste divided? 



Give evidence of special end organs for each division. 



How does cocaine affect the sensibility of the tongue? 



What is the function of the tongue? 



What is an after-taste? 



What are the organs of cutaneous sensation? 



